I'm looking forward to seeing the new addition to Trafalgar Square's Fourth Plinth: 'Nelson's Ship in a Bottle' by artist Yinka Shonibare. It will be launched on Monday 24 May.

John Gerrard's tunnel vision

Art on the Underground is one of London transport's greatest assets, bringing fun and culture to our daily journeys. Its latest commission to be unveiled is an installation by Irish artist John Gerrard in Canary Wharf station. 

As the suits descend the escalators in the futuristic, grey interior of the ticket hall they now face a different view – Gerrard's huge digital moving image of a landscape depicting a grain store in America. It's called 'Oil Stick Work (Angelo Martinez/Richfield, Kansas)’ and will be exhibited here for one year until 14 May 2011. Angelo Martinez is the small figure who is painting the barn black. The scene runs 24 hours a day, the light altering according to the time, and it turns showing different angles of the building.  

Gerrard is the only artist working in this hi-tech medium of realtime 3D and this work is designed to gradually build up digitally over 30 years – it began in 2008 and ends in 2038. 

I met the artist yesterday to discuss the purpose of public art. "All good art is public art in that it’s not selfish," says Gerrard. "It speaks to society in a real, meaningful sense. In this context the term is very appropriate because 45 million people use this station daily. It’s an ideal setting."

'Oil Stick Work' has an environmental message - like many of Gerrard's other works, it comments on depleting oil supplies. The site used to be one of the biggest oil producing regions of America and the work is due to reach completion on the day that American oil supplies are predicted to run dry. It's also in the artist's words, "a dreamscape", "an anti memorial", "an exit into another world", "a mirror to a computer-powered world". My favourite description of Gerrard's is, "It feels like a postcard inserted into this end of the station."

But the real significance of 'Oil Stick Work' is that it's constantly unfolding underneath the City, which was built on things such as oil and grain wealth. And, as well as the moral message, its minimalism suits the space, giving commuters a five-second glimpse of a work with many layers of meaning.  

The Jannis Kounellis litmus test

I like to play a game when I go to exhibitions – to try and guess what the artist is on about by simply looking at the art. This is the test of ‘good’, ‘successful’ art according to some critics, so I thought I’d try out the theory during my first visit to a Jannis Kounellis show at Ambika P3 gallery in Marylebone (on until 30 May). 

Looking round, I jotted down some notes: ‘reminds me of a past time’, ‘fits with the industrial-looking space’. The main installation (above) is like a coal train and standing next to it you can feel its gravity. The black fabric stretched across it looks like the curtains you get in the theatre. In the adjoining space, smart black coats hang in a sort of locker room – entering it there's a sense of isolation and it reminds me of London's banking culture. I especially liked the silk negligee strung up by a metal hook and wire – perhaps a feminist comment? But, what does all this mean? I'm still thinking about it – a sign of a good exhibition.

Upon reading the literature afterwards about Kounellis, a Greek artist living in Rome and a proponent of the Arte Povera movement (which is, in part, to do with using "found", recycled materials), I found that many of my observations were correct. He chooses the locations for his work carefully, having shown in warehouses, churches and castles before, he likes to integrate theatre into his work and the smaller pieces here symbolise human presence and man's existential difficulties. 

Kounellis, you've passed the test. I didn't need to read all your brochures to get some understanding of your work.  

http://p3exhibitions.com